الفهرس 
BETA-THALASSEMIAOnly 14 pages are availabe for public view
 |  | from | 125 |  |  |
| | | from | 125 | | |
Abstract
Background: Some published studies demonstrated proteinuria, aminoaciduria, low urine osmolarity, and excess secretion of the proximal tubule damage markers in pediatric patients with thalassemia. Serum cystatin C and urinary β2-microglobulin are promising biomarkers for monitoring glomerular and tubular dysfunction. Magnetic resonance imaging (MRI) gradient echo (T2*), the reciprocal of T2* (known as R*), has been developed to quantify tissue iron in the liver, the heart as well as the kidneys. Aim: To assess levels of serum cystatin C and urinary β2-microglobulin to albumin ratio as markers of renal functions (glomerular and tubular) among transfusion dependent β-thalassemia patients and their relation to iron overload and renal MRI (R2*). Methods: Fifty β-TM patients without symptomatic for renal disease were compared to 25 healthy controls and studied stressing on splenectomy, transfusion history, chelation therapy and serum ferritin. Urinary albumin excretion (UAE) was assessed in an early morning fasting urine sample as albumin-to-creatinine ratio (UACR) to detect micro- or macro-albuminuria. Serum levels of cystatin C and urinary β2 microglobulin were measured. Magnetic resonance imaging including the parameter R2 was used to measure iron content in kidney using a multiecho-gradient echo technique. Results: Serum cystatin C and urinary β2 microglobulin as well as UACR and urinary β2-M/albumin were significantly higher in β-TM patients than the control group. When the studied parameters of renal function were compared among patients with mean serum ferritin above or lower than 2500 µg/L, significantly higher serum cystatin C and urinary β2microglobulin as well as UACR and urinary β2-M/albumin were found to be associated with high ferritin cutoff. Significant positive correlations were found between serum cystatin C and total and indirect bilirubin, LDH, serum ferritin. Urinary β2 microglobulin was positively correlated to HbF levels and inversely correlated to hemoglobin levels. Serum cystatin C was positively correlated to renal R2* while negatively correlated to renal T2*. Multivariable linear regression analysis revealed that indirect bilirubin, LDH, serum ferritin, renal T2* and renal R2* were the significant independent variables related to increased cystatin C levels in patients with β-TM.Conclusion: We suggest that glomerular and tubular dysfunctions are common in pediatric patients with β-TM and are related to tissue iron overload. Further prospective studies are needed to examine the effect of different chelating agents on renal structural and functional integrity among β-TM patients.